Merge 08cec04 into 3469541

index.js

@@ -1,6 +1,7 @@
 'use strict';
 
 var rbush = require('rbush');
+var lineclip = require('lineclip');
 
 module.exports = whichPolygon;
 
@@ -22,13 +23,31 @@ function whichPolygon(data) {
 
     var tree = rbush().load(bboxes);
 
-    return function query(p) {
+    function query(p) {
         var result = tree.search([p[0], p[1], p[0], p[1]]);
         for (var i = 0; i < result.length; i++) {
             if (insidePolygon(result[i][4], p)) return result[i][5];
         }
         return null;
+    }
+
+    query.tree = tree;
+    query.bbox = function queryBbox(bbox) {
+        var result = tree.search(bbox).filter(function (el) {
+            // bbox is (possibly) completely inside the polygon. Keep it.
+            if (insidePolygon(el[4], [(bbox[0] + bbox[2]) / 2, (bbox[1] + bbox[3]) / 2])) return true;
+            // polygon crosses or is totally inside the bbox. Keep it.
+            // Todo: account for holes.
+            if (lineclip(el[4][0], bbox).length > 0) return true;
+            return false;
+        }).map(function (el) {
+            return el[5];
+        });
+
+        return (result.length === 1) ? result[0] : result;
     };
+
+    return query;
 }
 
 // ray casting algorithm for detecting if point is in polygon

package.json

@@ -4,6 +4,7 @@
   "description": "Index for matching points against a set of GeoJSON polygons",
   "main": "index.js",
   "dependencies": {
+    "lineclip": "^1.1.5",
     "rbush": "^1.4.1"
   },
   "devDependencies": {

test/test.js

@@ -7,9 +7,20 @@ var data = require('./fixtures/states.json');
 
 var query = whichPolygon(data);
 
-test('queries polygons', function (t) {
+test('queries polygons with a point', function (t) {
 	t.equal(query([-100, 45]).name, "South Dakota");
 	t.equal(query([-90, 30]).name, "Louisiana");
 	t.equal(query([-50, 30]), null);
 	t.end();
 });
+
+
+test('queries polygons with a bbox', function (t) {
+  t.equal(query.bbox([-100, 45, -99.5, 45.5]).name, "South Dakota");
+
+  var qq = query.bbox([-104.2, 44, -103, 45]);
+  var names = qq.map(function (el) { return el.name; }).sort();
+  t.equal(qq.length, 2);
+  t.like(names, ["South Dakota", "Wyoming"]);
+  t.end();
+});